Toluene → ethyl 8-but-1-ynyl-6-(trifluoromethoxy)-2-(trifluoromethyl)-2H-chromene-3-carboxylate

Participants

Reaction Steps

To a Parr bottle containing a mixture of ethyl 8-iodo-6-(trifluoromethoxy)-2-(trifluoromethyl)-2H-chromene-3-carboxylate prepared as in Example 21 a, Step 2 (1.00 g, 2.07 mmole), CuI (39 mg, 0.207 mmole), PdCl2(dppf)2.CH2Cl2 (167 mg, 0.0.207 mmole) and TEA (867 uL, 6.22 mmole) in anhydrous toluene (10 mL) was added at −78° C. 1-butyne (5 ml) and the bottle was sealed. After stirring for overnight at room temperature, additional CuI (390 mg, 2.07 mmole) and PdCl2(dppf)2.CH2Cl2 (1.67 g, 2.07 mmole) were added and the vessel was resealed. After stirring for 2.5 days, the mixture was cooled to −78° C. and additional CuI (200 mg, 1.05 mmole) and PdCI2(dppf)2.CH2Cl2 (0.500 g, 0.613 mmole), anhydrous toluene (10 mL) and 1-butyne (5 ml) were added and the vessel was resealed. After stirring at room temperature for 4 days, additional CuI (390 mg, 2.07 mmole) and PdCl2(dppf)2.CH2Cl2 (0.500 g, 0.613 mmole) were added and the vessel was resealed and stirred at room temperature overnight. The mixture was then poured into brine (100 mL) and extracted with EtOAc (200 mL). The extract was dried over MgSO4, filtered and concentrated in vacuo. Purification by silica chromatography (95:5 EtOAc:hexanes) gave the product as a crystalline solid: EIHRMS m/z 408.0773 (M+, C18H]4F6O4, Calc'd 408.0796).

Provenance & Evidence